Rotary screen printing machine equipped with improved squeegee system or the like

ABSTRACT

There is disclosed an improved rotary screen printing machine incorporating individual printing stations equipped with a substantially circular printing screen beneath which passes the backing cloth or printer&#39;&#39;s blanket supporting the material which is to be printed. A squeegee system or the like is inserted in the circular printing screen. According to the invention, the squeegee system which is mounted at both sides of the circular printing screen at the machine frame is constructed to be pivotable.

ited States Patent Inventor Heinrich Voegelin Wiler near Utzensdorf,Switzerland Appl. No. 761,773 Filed Sept. 23, 1968 Patented Jan. 26,1971 Assignee Fritz Buser AG, Maschinenfabrik Wiler near Utzensdorf,Switzerland a corporation of Switzerland Priority Sept. 26, 1967, Aug.20, 1968 Switzerland 13404/67 and 12500/68 ROTARY SCREEN PRINTINGMACHINE EQUIPPED WITH IMPROVED SQUEEGEE SYSTEM OR THE LIKE 8 Claims, 6Drawing Figs.

U.S.Cl..... 101/120 lnt.Cl B41l 13/06 Field ofSearch lOl/1l6,

[56] References Cited UNITED STATES PATENTS 1,480,348 1/l924 Cadgene etal. 101/120 2,445,666 7/l948 Ellam 101/119 2,928,340 3/1960 Stein et a1.lOl/lZO FOREIGN PATENTS 611,872 4/1935 Germany 101/120 493,l50 10/1938Great Britain..... 10l/120 513,905 lO/l939 Great Britain l0l/l20 PrimaryExaminerRobert E. Pulfrey Assistant ExaminerAlan E. KopeckiAtt0rneyWerner W. Kleeman ABSTRACT: There is disclosed an improvedrotary screen printing machine incorporating individual printingstations equipped with a substantially circular printing screen beneathwhich passes the backing cloth or printers blanket supporting thematerial which is to be printed. A squeegee system or the like isinserted in the circular printing screen. According to the invention,the squeegee system which is mounted at both sides of the circularprinting screen at the machine frame is constructed to be pivotable.

PATENTED JANZ 6197i sum 1 or 4 FIG. 1

FIG. 2

INVENTOR Hgmmlk Monmm 4m #9..-

ATTORNEY.

ATENTEU JAN 2 6197| SHEET t Of 4 INVENTOR ifil m ATTORNEW ROTARY SCREENPRINTING MACHINE EQUHPED WITH IMPROVED SQUEEGEE SYSTEM Olit THE LIKEBACKGROUND OF THE INVENTION The present invention broadly relates to animproved rotary screen printing machine and, in its more specificaspect, concerns an improved arrangement of the squeegee system or thelike associated with the circular printing screen.

Rotary screen printing techniques constitute a continuous printingmethod in which the material. is printed upon by means of circularprinting screens or the like. The printing ink or dye is delivered intothe interior of the circular printing screen and escapes through thefine perforated screen material. Although rotary screen printingmachines permit of a continuous operation, still it is impossible toprevent interruptions in the working cycle. Upon stopping the printingoperation, whether it be because of changing the printing ink or for anyother reasons, the printing ink immediately passes through theperforations of the circular printing screen and soils the fabric ormaterial to be printed or at the very least the backing cloth orprintcrs blanket. Furthermore, during longer down times of the machinethe danger exists that the ink will, apart from soiling the printer'sblanket, also contaminate further components of the machine.

SUMMARY OF THE INVENTION It is a primary object of the present inventionto effectively overcome these drawbacks.

A more specific object of the present invention relates to an improvedrotary screen printing machine wherein the squeegee system or the likeis constructed in such a manner that during nonuse of the machine, it ispossible to prevent contamination of the material being printed, theprinters blanket and other parts of the machine by the printing ink.

Still a further significant object of the present invention relates toan improved rotary screen printing machine which is relatively simple inconstruction, extremely reliable in operation, requires a minimum ofservicing and maintenance, and effectively prevents improper contact ofthe printing ink with the material being printed or other components ofthe machine.

Another, more specific object of the present invention relatcs to animproved rotary screen printing machine provided with means which insurethat the printing ink is returned to a location where it cannotunintentionally come into contact with the material upon which theprinting operation is carried out during such time as the machine isbrought to a standstill Now, in order to implement these and stillfurther objects of the invention, which will become more readilyapparent as the description proceeds, the invention contemplatesconstructing the squeegee system which is mounted at both sides of thecircolor printing screen at the machine frame so as to be pivotable.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood, and objects other than those set forth above, will becomeapparent, when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. I is a schematic sectional view through a circular printing screenequipped with an inserted squeegee system and shown in its printingposition; and

FIG. 2 is a sectional view through the circular printing screen withinserted squeegee system, corresponding to the arrangement of FIG. 1,but depicting the printing screen and the associated squeegee system ina rest position;

FIG. 3 is a sectional view taken through a support equipped with thebearing or support means for the squeegee system of the rotary screenprinting machine, and taken along the lines l-l ofFIG. 4;

FIG. 4 is a front view showing detailsof the support or mounting for thesqueegee system as viewed from the nonserviced side of the machine, thatis to say, at the side where the ink is introduced;

FIG. 5 is a front view of the support or mounting for the squeegee ystemas viewed from the servicing side of the machine; z, nd

FIG. 6 is a fragmentary view showing a detail of the squeegee supporttube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,it will be understood that reference numeral 1 designates thesubstantially circular printing screen which is constructed as afine-perforated thinwall hollow cylinder member. This circular printingscreen I is rotatably mounted in suitable fashion at both sides of thenonillustrated machine frame. As is known to those versed in the art,the circular printing screen 1 is appropriately driven in synchronismwith the backing cloth or printer's blanket 2. The material or fabric 3which is to be printed is carried on the printers blanket 2 and thismaterial is suitably fixed thereon. Moreover, the printer's blanket 2 isprestressed or tensioned in an appropriate way and forms a smoothprinting support. In order to be able to carry out a faultless printingoperation a conventional nonillustrated counterpressure roller isadvantageously arranged beneath each circular printing screen 1, but hasbeen omitted to preserve clarity in illustration.

The support means for the circular printing screen 1, as also is thecase with the circular printing screen itself, possesses a rather largefree opening through which it is possible to introduce the squeegeesystem, generally designated by reference character 20. This squeegeesystem 20 or equivalent structure serves for the introduction of theprinting ink or dye to the inner jacket surface of the printing screen 1and also provides for a proper dosage of such printing ink. In theexemplary illustrated embodiment, it will be recognized that thesqueegee system 20 embodies a de1ivery-or squeegee tube 4 which servesas a squeegee support and carries the squeegee 5 as well as the flowcontrol squeegee 6.

The squeegee system 20 is rotatably mounted at both sides of thecircular printing screen 1 externally at the machine frame in a mannerwhich will be explained more fully hereinafter. As already alluded toabove, this squeegee system 20 is disposed within the circular printingscreen 1 and also passes through the support means for the circularprinting screen. The rotational support for the squeegee system isbrought about through the provision of two segments 9 arranged at bothsides of the machine frame, and between which the squeegee system 20 isarranged. These segments 9 are rotatably secured at the pivot points 10at the machine frame. A slit II is provided at each segment 9 whichrenders possible the raising and lowering of the squeegee system, inorder to thereby accommodate the squeegee 5 to the diameter of theprinting screen 1, to adjust for the desired squeegee pressure and to beable to compensate for any wear of the squeegee.

The rotatable attachment arrangement for the squeegee system functionsin the following manner:

Directly after stopping of the rotary screen printing machine thedescribed apparatus is rotated in the direction of the arrow 12 aboutthe point of rotation 10 which is disposed or located at the middle orcentral region of the circular printing machine, until it assumes therest position shown in FIG. 2. Now, the printing ink located within thecircular printing screen I flows along the flow control squeegee 6downwards and is caught by the catch nose '7. The printing ink, asgenerally indicated by the arrow 14, flows through the bore means 8 backinto the squeegee tube t.

If the printing operation is then continued, then the describedapparatus is rotated further in the direction of the arrow 15 andbrought into the printing position. The transition from the printingposition to the rest position can advantageously be undertaken by meansof a suitable drive motor, and specifically in such a fashion that uponactuation of this motor the squeegee system is rotated into the restposition and retained at such location, whereas upon further actuationof the drive motor the squeegee system is brought from the rest positioninto the printing positionand retained in the latter location.

it should be'understood that for the practical operation of theaforedescribed apparatus it isof importance that the squeegee system canbe easily dismantled and removed. FIGS. 3 to 6 illustrate a particularlyadvantageous solution for the pivotal mounting of the squeegee system.Referring to these figures now, it will be understood that referencenumerals 101 and 102 designate the support means which are carried atboth sides of the nonillustrated machine frame. The circular printingscreen, which is not visible in these figures, is rotatably mounted insuch support means 101, 102. More specifically, the circular printingscreen is secured to the sup port or bearing body member 103 sewing forthe mounting of the printing screen, and, if desired, such printingscreen can be secured to this bearing body member 103 through theintermediary of elastically flexible intermediate body means, in amanner not shown in greater detail herein since it is not neces- V saryfor the understanding of the inventive concepts Continuing, it should beunderstood that the support or bearing body 103 is mounted in bearingmeans 104, 105, and driven via a gear 106. As best recognized byreferring to FIG. 3, a number of segments 107 are secured to the support101 with the help of screws 108 or equivalent fastening expedients.These segments 107 provide a support arrangement for a ring member 109carrying the squeegee system or unit. This ring member 109 is rotatablymounted in the support segments 107.

Furthermore, it will be understood that at the oppositely situatedsupport 102 a further ring member 110 is mounted in exactly the samemanner. At least one of both rings 109, 110 possesses an externallytoothed portion 111, in this case shown provided at ring 109, whichtoothed portion 111 meshes with the teeth of a counter gear 112. Asuitable time mover or power source, schematically indicated byrefefence numeral 200, serves to drive the ring 11 1 by means ofthe'gear 112. it has been found that the prime mover 200 can"advantageously be a hydraulic motor which, for instance, receives itspressurized medium from the pressurizedmedium network already availableat the machine and required for the lowering of the printing components.

By best referring to FIGS. 4 and 5, it will be recognized that the ringmembers 109 and 110 carry lever members 113 and 114, respectively, whichare, in turn, pivotally mounted at the pivot pins 115 and 116,respectively, arranged at the aforesaid ring members 109 and 110.Suitable adjustment means 117 and 118 are provided at the respectivefree ends of the respective lever members 113 and 114. Each of theseadjustment means 117 and 110 is composed of a manually operablespindle-stroke adjustment mechanism 117a and 110a respectively,

supported at the ring members 109 and 110, respectively. The

stroke adjustment mechanisms 1l7aand 118a of the adjustment means 117and 118 respectively, are hingedly connected by means of bolts 119 and120, respectively, to the associated levers 113 and 114 and serve foradjusting the position of such associated lever with respect to theassociated ring member v109 and 110. Furthermore, it will be recognizedthat a stop member 121 and 122 is arranged at the respective ringmembers 109 and 110. In the working position of the squeegee systemthese stops 121 and 122 bear against adjustable stop members 123 and124, respectively, and in the rest position of the squeegee system, suchstops 121 and 122 bear against stationary arranged stop means 125 and126, respectively,arranged at the support members 101 and 102respectively.

1 The squeegee system is mounted at both of the lever members 113 and114. Thissqueegee system is composed of a squeegee support tube or pipe127, typically formed of rustproof or stainless steel, and whichpossesses a smaller diameter, as indicated by reference numeral 128, atthe ink infeed side of such tube 127 than the remaining portion 129 ofsuch All tube. At the servicing side of the machine this tube is locatedin a bore 130 of the lever member 114, through which there is guided apin member 131. This pin member 131 fits in a slot or groove 132 (seeFIGS. 5 and 6) arranged at the plug member 133 by means of which thetube 127 while utilizing an O-ring 134 is sealed. The bore 130 possessessufficien t play so that the squeegee support tube 127 can be introducedat an inclination from the ink delivery side until the pin member 131 isdisposed in the slot or groove 132, whereby entrainment of the squeegeesystem is insured.

The mounting of the squeegee support or mounting tube 127 at the inkdelivery side deviates from the mounting arrangement provided at theservicing side of the machine. More precisely, by referring to F161 4 itwill be recognized that two rectangular blocks135 and 136 are fixedlyclamped with the tube portion 128 by means of two screws for instance orequivalent fastening devices. One of these two blocks, such as the block136 is somewhat larger than the other and fits into a suitable recess137 provided at the lever'member 113 and is engaged by two cams or dogs138 and 139, as shown. Consequently, the squeegee support or mountingtube 127 can only be axially removed or withdrawn. The removal of thesqueegee support tube and the squeegee system initially occurs throughaxial displacement of the tube 127 until the blocks 135 and 136 arepushed out of the support or recess 137 of the lever 113. Thereafter,the squeegee system can be lifted and moved out of the opening providedat the ring member 109. The remounting of the squeegee unit isundertaken in thesame way but with a reverse sequence of steps. Thesqueegee system is introduced at an inclination into the bore 130, priorto reaching the support 137 is lowered by means of the blocks 135 and136 into the horizontal position and the terminal position is reached bycarrying out axial displacement, so that the pin 131 again engages inthe slot 132 and the bloel 136 engageswith the support or recess 137 ofthe lever 113.'ln order to fix the position of the squeegee system thereis advantageously provided a spring loaded stop arrangement 140 whichprevents an axial displacement of the squeegee system during operation.

While keeping the foregoing in mind, it will be recognized that in orderto, pivot or rock the squeegee system into the rest position the ringmembers 109, 110 are rotated through about 180 in counterclockwisedirection from the position shown in FIG. 5 and through the action ofthe prime mover or drive means 200 and via the gear 112, as previouslyexplained, until the cam means or steps 121 and 122 bear against thefixed stops 125 and 126 respectively. Thesqueegee system is rigidlyconnected for rotation by means of the pin 131 with the lever members113, 114 and thus rotates together with the movement of the ring members109 and 110. By means of the movable or adjustable stops or stop members123 and 124 it is possible to adjust the position of the squeegee in thework position through an angular range designated by the angles 0:62.This adjustment possibility is of considerable importance for attaininga faultless printing operation at the material or fabric and the settingis undertaken in accordance with the type of ink or dye which is usedand the momentarily employed circular printing screen.

A further adjustment possibility for the squeegee is provided byvirtueof the spindle-stroke adjustment mechanisms 117a and 1184 of theadjustment devices 117 and 118 respectively. By virtue of thisadjustment feature it is possible to adju'st the squeegee considerablyin the radial direction. Consequently, the squeegee pressure can beregulated and any wear of the squeegee itself can be compensated quiteeasily.

The possibility of being able to pivot or rock the squeegee within apredetermined angular range provides the advantage of enabling asimplification of the construction of the squeegee support profile 143,which in its basic structure consists of three ribs or webs 143a and issecured in suitable fashion to the squeegee tube 127; As best shown byreferring to FIG. 5, two of these ribs 143a serve for fixedly clampingthe squeegee 142, whereas the third rib or web forms together with bothof the clamping ribs for the squeegee 142 a trough 143b when thesqueegee system is rocked into the rest position. The ink accumulationsor clots can flow into this trough 143b and from this location the inkcan flow through bore means 144 back into the squeegee tube or pipel29.In this in: stance the normally employed flow control squeegee can beomitted since, due to the possibility of adjusting the squeegee 142either opposite or in the direction of travel A of the material to beprinted the printing operation, especially as concerns the dosing of thequantity of printing ink, can be int'luenced in the same manner as ispossible with a flow control squeegee of the type previously consideredinconjunction with FIGS. 1 and 2.

It should be apparent from the foregoing detailed description, that theobjects set forth at theoutset to the specification have beensuccessfully achieved.

I claim:

1. A rotary screen printing machine of thetype incorporating individualprinting stations provided with a substantially circular printingscreen, a printers blanket for the material to be printed passingbeneath said circular printing screen, a squeegee system inserted insaid circular printing screen for expressing printing ink through saidcircular printing screen, means for pivotably mounting said squeegeesystem at both ends of said circular printing screen, said mountingmeans for said squeegee system incorporating a support at each end ofsaid circular printing screen in which said screen is rotatably mounted,a ring member rotatably carried by each support for rotatably supportingsaid squeegee system with respect to said screen, a respective levermember pivotally secured to each of said ring members and serving tosupport said squeegee system, drive mechanism for rotating said ringmembers with respect to said screen, and adjustment means cooperatingwith each of said lever members and secured to each associated ringmember for pivoting the associated lever member with respect to itsassociated ring member.

2. A rotary screen printing machine as defined in claim 1, wherein saidsqueegee system incorporates a squeegee tube defining an infeed tube forthe printing ink, said squeegee tube being provided with bore means,said squeegee system when pivoted into a rest position causing theprinting ink to flow back through said bore means into said squeegeetube.

3. A rotary screen printing machine as defined in claim 1, wherein saidsqueegee system includes a squeegee tube, and wherein said adjustmentmeans defines mechanism permitting radial adjustment of said squeegeetube with respect to the circular printing screen.

4. A rotary screen printing machine as defined in claim 1, furtherincluding stop means for adjusting and limiting the pivotable movementof said squeegee system.

5. A rotary screen printing machine as defined in claim 4, wherein atleast one of said ring members is provided with external teeth means,said drive mechanism including gear means engaging with said externalteeth means for pivoting the associated ring member, and a drive motorfor driving said gear means.

6. A rotary screen printing machine as defined in claim 5, wherein saiddrive motor comprises hydraulic motor means.

7. A rotary screen printing machine as defined in claim 4, wherein saidsqueegee system incorporates a squeegee element, said stop means foradjusting the pivotal movement of said squeegee system serving toregulate the point of application of said squeegee element to both sidesof its vertical position within a predetermined angular range.

8. A rotary screen printing machine as defined in claim 4, wherein saidsqueegee system comprises a squeegee tube, a squeegee support profilemember having three webs secured to said squeegee tube, two of said websbeing adapted to fixedly clamp a squeegee therebetween, and the third ofsaid webs cooperating with said squeegee clamping webs to form a troughfor receiving the printing ink when the squeegee system assumes a restposition, and bore means communicating said trough with said squeggeetube in order to permit the printing mk to pass via sai bore means backinto said squeegee tube.

1. A rotary screen printing machine of the type incorporating individualprinting stations provided with a substantially circular printingscreen, a printer''s blanket for the material to be printed passingbeneath said circular printing screen, a squeegee system inserted insaid circular printing screen for expressing printing ink through saidcircular printing screen, means for pivotably mounting said squeegeesystem at both ends of said circular printing screen, said mountingmeans for said squeegee system incorporating a support at each end ofsaid circular printing screen in which said screen is rotatably mounted,a ring member rotatably carried by each support for rotatably supportingsaid squeegee system with respect to said screen, a respective levermember pivotally secured to each of said ring members and serving tosupport said squeegee system, drive mechanism for rotating said ringmembers with respect to said screen, and adjustment means cooperatingwith each of said lever members and secured to each associated ringmember for pivoting the associated lever member with respect to itsassociated ring member.
 2. A rotary screen printing machine as definedin claim 1, wherein said squeegee system incorporates a squeegee tubedefining an infeed tube for the printing ink, said squeegee tube beingprovided with bore means, said squeegee system when pivoted into a restposiTion causing the printing ink to flow back through said bore meansinto said squeegee tube.
 3. A rotary screen printing machine as definedin claim 1, wherein said squeegee system includes a squeegee tube, andwherein said adjustment means defines mechanism permitting radialadjustment of said squeegee tube with respect to the circular printingscreen.
 4. A rotary screen printing machine as defined in claim 1,further including stop means for adjusting and limiting the pivotablemovement of said squeegee system.
 5. A rotary screen printing machine asdefined in claim 4, wherein at least one of said ring members isprovided with external teeth means, said drive mechanism including gearmeans engaging with said external teeth means for pivoting theassociated ring member, and a drive motor for driving said gear means.6. A rotary screen printing machine as defined in claim 5, wherein saiddrive motor comprises hydraulic motor means.
 7. A rotary screen printingmachine as defined in claim 4, wherein said squeegee system incorporatesa squeegee element, said stop means for adjusting the pivotal movementof said squeegee system serving to regulate the point of application ofsaid squeegee element to both sides of its vertical position within apredetermined angular range.
 8. A rotary screen printing machine asdefined in claim 4, wherein said squeegee system comprises a squeegeetube, a squeegee support profile member having three webs secured tosaid squeegee tube, two of said webs being adapted to fixedly clamp asqueegee therebetween, and the third of said webs cooperating with saidsqueegee clamping webs to form a trough for receiving the printing inkwhen the squeegee system assumes a rest position, and bore meanscommunicating said trough with said squeegee tube in order to permit theprinting ink to pass via said bore means back into said squeegee tube.